View Full Version : Dont really understand the sound

12-02-2012, 09:16 PM
Hi I have a 2001 Volvo C70 convertible and it has a good sound system from the factory, it has a center channel, a 8 inch sub in each door and a 4 inch speaker in each door, tweeters in the dash and 400watts from a alpine V12.
I just started driving the car and I noticed a big difference in sound quality from radio to CD witch I excepted. What I don't understand is the Dolby Pro-logic. Their is a button on the face of the radio that I can switch from stereo, to stereo with center channel and then a Pro-logic setting. I've been listening to music on the three different settings and I can tell the difference between them. I am wondering why the Pro-logic setting seams to have more back ground noise or maybe its "mid fill" sound. It is just a different sound that I am not used to, do you think the Pro-logic setting amplifies the mid range? and that is what it am hearing?
Is that what "better" sound quality sounds like?

I am really looking forward to installing some sound damping materiel in the doors, up-grading the subs and mid speakers and hearing the results from my effort because the sound system sounds very good now in stock form.

12-02-2012, 10:49 PM
Pro-Logic probably converts 2-channel stereo sound into a 5.1-channel sound so that an appropriate signal is sent to the center channel speaker, sides, and surrounds. Some processing is done to take advantage of the center channel speaker to create a centered sound stage. Things that are supposed to be in the center of the sound stage, such as voices should be primarily sent to the center channel. Rear speakers are sent only surround effects, etc.

If you don't like the Pro-Logic implementation of 5.1 sound you have, I suggest to check out JBL's MS-8 processor. It has 5.1 sound processing called Logic 7 which reportedly works a lot better in the cars. It can also do things like clear up your frequency response, etc by running a calibration sequence with a microphone. It does need a clean stereo signal to work with.

12-03-2012, 12:07 AM
O ok I understand, I've just been playing with the sound system and I was wondering what was happening? My plan is to up-grade the sound system components but keep the factory head unit as long as possible and then when I do up-grade the HU I will put in a very high quality one so I can adjust everything.
Thanks for the advice.

12-03-2012, 05:05 AM
Well, you will not be able to retain the 5.1 sound capability without the factory head unit. If you do upgrade the factory head unit, then adding a JBL MS-8 or Alpine H800 may be a good idea as they can convert stereo signal to 5.1 if that's what you like to use.